Hi,

I would suggest you to check if the same issue is seen safemode ,if it is then its a software issue.

Also send the service tag of the system via private message and a screen shot of the display showing the black border would be helpful.

Awaiting your reply.

Regards,

Likely its the graphics driver Windows 10 has installed. Try to install the updated Dells drivers:

http://downloads.dell.com/FOLDER03205670M/3/Application_Intel%20WiDi_WIN1064_A00_DFX88-Setup_ZPE.exe

http://downloads.dell.com/FOLDER02225864M/1/Serial-ATA_Driver_DPK7T_WN_13.0.0.1098_A01.EXE

http://downloads.dell.com/FOLDER03326858M/1/Video_Driver_JY2H3_WN32_10.18.15.4278_A01.EXE

http://downloads.dell.com/FOLDER03160578M/1/Audio_Driver_GKHWY_WN32_6.0.1.7525_A00.EXE

http://downloads.dell.com/FOLDER03168044M/3/Input_Driver_GGWTC_WN32_19.0.9.4_A00.EXE